<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- function Person(name) {
        this.name = name;
      }
      
      Person.prototype.sayHello = function() {
        console.log(`Hello, my name is ${this.name}`);
      };
      
      function Student(name, major) {
        Person.call(this, name);
        this.major = major;
      }
      
      Student.prototype = Object.create(Person.prototype);
      Student.prototype.constructor = Student;
      Student.prototype.sayMajor = function() {
        console.log(`My major is ${this.major}`);
      };
      
      const john = new Student("John", "Computer Science");
      1.请解释这段代码的作用。
      2.john能够调用哪些方法？
      3.如果我们在Student的原型对象上添加一个名为sayHello的方法，会发生什么？ -->
</body>
</html>